Abstract: Apparatus for controlling a hydraulically driven generator for supplying electrical power to power mains. The generator is coupled to a turbine driven by a fluid flow through a duct. The duct has a one-fourth turn butterfly valve controlled by a fluid-actuated operator and the operator receives fluid from the duct by way of a normally closed valve which, when energized, creates water pressure on the operator for opening the butterfly valve. A second, normally open solenoid provides an emergency exit for the water from the operator to relieve the water pressure thereon and thereby close the butterfly valve when certain conditions exist, such as sudden loss of line voltage, overvoltage or deviation in frequency of the line voltage. A differential pressure switch across the turbine rotor also controls the starting of the system to assure proper flow of fluid through the duct before commencing operation of the generator itself.

Abstract: A compressor, condenser, pressure control valve, condensed liquid receiver, expansion valve and evaporator are arranged in circuit to provide a refrigeration system. The pressure control valve and condensed liquid receiver are bypassed by a pump tank and a pump in circuit between the output of the condenser and the expansion valve. A float switch in the pump tank provides an actuating signal at a predetermined level for condensed liquid in the pump tank, and the actuating signal is coupled to the pump. The pump, when actuated, draws condensed liquid from the pump tank at a free condensation pressure dependent upon ambient temperature at the condenser, and provides high pressure condensed liquid to the expansion valve. An inlet/outlet line between the condensed liquid receiver and the expansion valve allows high pressure condensed liquid which is not passed by the expansion valve to be accumulated in the condensed liquid receiver.

Abstract: An energy saving refrigeration system as for refrigerated display cases in stores, free of the usual winter head pressure controls on the condenser equipment, capable of functioning satisfactorily with two-phase, liquid-gas mixtures of refrigerant inlet flow, there being a pair of valves immediately upstream of the evaporator, one being an expansion valve, and the other being a pressure regulator just upstream of the expansion valve adjusted such as to maintain a fixed discharge pressure to the expansion valve, this regulator discharge pressure set sufficiently above the evaporator boiling pressure and set sufficiently below the minimum inlet pressure to the pressure regulator.

Abstract: A multiple curtain, refrigerated display case employing an energy saving air defrost system that, during the first defrost stage, draws defrosting ambient air into the refrigerated air curtain passage from both directions, and during the second defrost stage employs part of the defrost air to form a circulating air curtain over the open front of the case. The case has defrost exhaust fans in the upper rear thereof actuated by a timer simultaneously with deactuation of the guard curtain fans and the refrigeration condensing unit. The circulation fans for the refrigerated air of the case have a total propulsive capacity significantly greater than that of the exhaust fans, such refrigerated air circulation fans being upstream of the refrigeration coils in the refrigerated air curtain passage, and the exhaust fans being downstream of such coils.